State of the art methods and apparatus for providing external cardiac resuscitation are discussed to some extent in U.S. Pat. No. 5,806,512 (“'512 patent”). The '512 patent teaches the use of inflatable cuffs surrounding a patient's chest, abdomen and legs which are periodically inflated and deflated to force blood from the extremities to and through the heart with the chest and abdomen functioning in an out-of-phase relationship. Ventilation via a patient mask is also disclosed in the patent.
More recently a portable resuscitation/ventilation system using inflatable chest, abdominal and leg cuffs and a ventilator coupled to self-contained cylinders of compressed gas is described in international publication WO 2010/151278 A1 (“'278 pub.”) and disclosed on the web site AutoCPR.net. Solenoid operated valves, controlled by an electronic timer, connect the cuffs alternately to the compressed gas cylinders and to the ambient or atmosphere to inflate and deflate the cuffs in a timed sequence. For example, the chest and abdominal cuffs are operated in an out-of-phase sequence at a 30 cycles per minute rate, i.e., one second on (inflation) and one second off (deflation). The leg cuffs can be inflated and deflated at the same or a different rate. For example, the leg cuffs can be inflated continuously or inflated/deflated every fifth cycle of the chest cuff with the inflation period exceeding the deflation period. The portable gas supply is designed to provide adequate time to achieve the return of spontaneous circulation (ROSC) and patient transport to a hospital emergency department. A face mask and a tank of breathable gas provide ventilation for the patient. The resuscitator/ventilator of the '278 pub. is small enough to fit into a suitcase easily handled by a paramedic or other first responder. While it is believed to be cutting edge for its intended purpose, the use of compressed gas cylinders limits its operating time.
Recent clinical studies have demonstrated that the continued support of a patient's circulation (such as uninterrupted chest compression) after ROSC significantly improves the survival rate of patients after leaving the hospital. See, for example, the Journal of Emergency Medicine, 1008, Feb. 12, 2009 by M. Riscon, et al; the European Resuscitation Council Guideline for Resuscitation 2005 by A J Hadley, et al; Critical Care 2005, 9:287-290 by M H Weil and Shijie Sun; and Burst Stimulation Improves Hemodynamics during resuscitation etc. in Circulation: 2009, 2:57-62 by G. Walcott et al.
There is a need for a system/apparatus which will not only aid in achieving a patient's ROSC but in addition continue to support the patient's circulatory system over an adequate time period after ROSC to improve the out of hospital survival rates for patients suffering cardiac arrest or other serious heart problems.